Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude [PDF]
, 2020 The Sun exhibits a well-observed modulation in the number of spots on its disk over a period of about 11 years. From the dawn of modern observational astronomy, sunspots have presented a challenge to understanding—their quasi-periodic variation in number,
McIntosh, Scott W. +4 more
core +1 more source
Prediction of solar activity on the basis of spectral characteristics of sunspot number [PDF]
Annales Geophysicae, 2004 Prediction of solar activity strength for solar cycles 23 and 24 is performed on the basis of extrapolation of sunspot number spectral components. Sunspot number data during 1933-1996 periods (solar cycles 17-22) are searched for periodicities by ...
E. Echer +4 more
doaj +1 more source
Re-examining sunspot tilt angle to include anti-Hale statistics [PDF]
, 2014 Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data ...
Li, J., McClintock, B. H., Norton, A. A.
core +1 more source
Heartbeat of the sun from principal component analysis and prediction of solar activity on a millenium timescale [PDF]
, 2015 We derive two principal components (PCs) of temporal magnetic field variations over the solar cycles 21-24 from full disk magnetograms covering about 39% of data variance, with σ = 0.67. These PCs are attributed to two main magnetic waves travelling from
Shepherd, Simon J. +10 more
core +1 more source
Differential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUC
The Astrophysical Journal, 2023 Solar differential rotation is an important ingredient of the solar dynamo model, not only because the solar rotation profile is one of the key inputs in a solar dynamo model, but also because it imposes constraints for the solar dynamo model.
Miao Wan +3 more
doaj +1 more source
Evolution of sunspot properties during solar cycle 23
, 2011 The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle. We aim to determine a number of sunspot properties over cycle
Watson, F. +6 more
core +3 more sources
Long-term solar activity explored with wavelet methods [PDF]
Annales Geophysicae, 2006 Long-term solar activity has been studied with a set of wavelet methods. The following indicators of long-term solar activity were used; the group sunspot number, the sunspot number, and the 14C production rate.
H. Lundstedt +3 more
doaj +1 more source
Active Days around Solar Minimum and Solar Cycle Parameter
Journal of Astronomy and Space Sciences, 2021 Utilizing a new version of the sunspot number and group sunspot number dataset available since 2015, we have statistically studied the relationship between solar activity parameters describing solar cycles and the slope of the linear relationship ...
Heon-Young Chang
doaj +1 more source
Sunspot numbers: Implications on Eastern African rainfall
South African Journal of Science, 2014 Following NASA’s prediction of sunspot numbers for the current sunspot cycle, Cycle 24, we now include sunspot numbers as an explanatory variable in a statistical model. This model is based on fitting monthly rainfall values with factors and covariates
Francis Gachari +2 more
doaj +1 more source
Time variations of the ionosphere at the northern tropical crest of ionization at Phu Thuy, Vietnam [PDF]
Annales Geophysicae, 2011 This study is the first which gives the climatology of the ionosphere at the northern tropical crest of ionization in the Asian sector. We use the data from Phu Thuy station, in Vietnam, through three solar cycles (20, 21 and 22), showing the complete
H. Pham Thi Thu +3 more
doaj +1 more source